For this type of lens machining apparatus, conventionally, a grindstone type lens machining apparatus has been used wherewith the lens circumferential edge is machined into the prescribed shape by grinding (edging) the circumferential surface of the lens with a grindstone. Insofar as plastic lenses are concerned, however, it is possible to do this by edging and machining. More recently, therefore, edging (cutting) type lens machining apparatuses have been developed wherewith the lens circumferential surface is edged (cut) with a cutter. This type of edging lens machining apparatus is disclosed in Japanese Patent Application Laid-Open No. H9-309051/1997 (published) and Japanese Patent Application Laid-Open No. H11-028650/1999 (published), for example. In Japanese Patent Application Laid-Open No. H4-315563/1992 (published) and Japanese Patent Application Laid-Open No. H5-4156/1993 (published), moreover, technology is disclosed for setting and altering the grinding (edging) load on the grindstone according to the lens circumferential edge thickness, with the object of preventing lens cracking and efficiently performing suitable machining in cases where the circumferential surface of a lens is ground (edged) with a grindstone (revolving machining tool for machining circumferential surfaces) and the lens circumferential edge is machined to a prescribed shape.
However, with the edging type lens machining apparatus described in Japanese Patent Application Laid-Open No. H9-309051/1997 (published) and Japanese Patent Application Laid-Open No. H11-028650/1999 (published), executing the entire machining menu demanded for eyeglass lenses with a single chuck operation in one apparatus (where a single chuck operation means one lens holding operation wherewith there is no movement of a lens between different apparatuses) is something that still cannot be done. More specifically, in an ordinary eyeglass lens machining menu,                (1) lens circumferential surface edging and machining (inclusive of bevel edging)        (2) machining for forming grooves in lens circumferential surfaces, and        (3) chamfering edges where the lens circumferential surface and lens faces intersectare included, but it has not been possible to handle all of these menu items with one chuck operation in one apparatus. In particular, because high machining precision is demanded in bevel edging, groove machining, and chamfering, the ideal is to be able to do this with one chuck operation, inclusive of measuring the shape and position of the lens being machined, but art wherewith that can be done has not been available. Nor has it always been possible, merely by setting and altering the grindstone grinding (edging) load according to the lens circumferential thickness, as in the art described in Japanese Patent Application Laid-Open No. H4-315563/1992 (published) and H5-4156/1993 (published), to perform machining of good precision or machining exhibiting good finished surfaces.        
An object of the present invention, in view of the situation described in the foregoing, is to provide a lens machining apparatus and lens machining method wherewith the machining demanded for eyeglass lenses, from measurement to various machining items, can be accomplished with a single chuck operation, and wherewith it is possible to realize high-precision machining.